Bevel and hypoid gears can be cut in a single indexing process (face milling) or in a continuous indexing process (face hobbing). A basic cutting setup in the generating or cradle plane will put the center of the cutter head in a position which is away from the generating gear center (cradle axis) by the amount of the so-called radial distance. The silhouette of the cutter blades represents one tooth of the generating gear while the cutter rotates). Common face cutters for bevel gear cutting have several blade groups with each group having between one and four blades. Most common types of face cutters are alternating (completing) cutters with one outside and one inside blade.
In most stick blade cutter systems, the cutting blades have a rectangular blade cross section are usually secured in a cutter head via a friction seating between clamp blocks or clamp screws and a radial seating surface of the cutter head. An example of positive blade seating is shown in U.S. Pat. No. 6,120,217 which incorporates a pentagon shaped cross section with two specially oriented seating surfaces. It is very important for cutting blade (especially if the blade material is carbide) to achieve a stiff and precise seating between the blades and the cutter head. One purpose of a clamping system is the precise positioning and a high seating stiffness of cutting blades without any blade movements during a tool life run which, for example, may be more than 8 hours of continuous gear cutting.
There are some known types of cutter systems with positive blade seating which have found limited industrial utilization. Included in these cutter systems are those utilizing blades with circular or half circle shaped cross sections (for example, U.S. Pat. No. 5,934,841 and EP 1240966 A2). Tapered wedge clamp combinations are used in those systems to press the cylindrical blade sticks into round holes oriented around the circumference of the cutter head body. US 2011/0164931 uses a complex differential tandem wedge to clamp blades with a rectangular cross section into the corner of a rectangular cutter head slot. In the above cases, round or rectangular, the blades are wedged into the seating surfaces with self-locking clamp components. Truing requires tapping with a hammer in order to release the wedges and free the blades for axial movement. Precise cutter head building requires the ability to relieve the clamping forces of the clamping system without disturbing the axial blade location in order to move the blades axially by small amounts relative to their previous position. Such a truing procedure is not possible with self- locking systems wherein impacts from a tool, such as a hammer or screwdriver for example, are required before a blade can be axially moved.